This invention relates to encoding and previewing of search string data.
In network test environments, for example, a technician is often looking for particular data strings, for the purpose of debugging or testing the network, or searching for networking problems or event occurrences.
Communications protocols have generally well defined structures consisting of specifications for the order and contents of fields within a message. Fields within a data stream in a given protocol may be sent in packets, a combination of values that control the flow of data, sometimes referred to as protocol header fields, or payload fields that contain information that is exchanged between devices on a network.
Information contained in a packet is often “encoded” to facilitate efficient processing by the computer applications that generate or consume the packet.
Since a network may be employing a variety of communication protocols and data encoding types, it can be cumbersome or impossible to find a particular data set or string in raw data received by a network test instrument.
The strings may be plain text, e.g. “uspto”, but are more likely specific values described by the protocol a user is attempting to troubleshoot. Even plain text maybe encoded within a data packet using several different schemes, such as ASCII or Unicode. The protocol, the network or the operating systems of the devices being monitored may also affect the “byte order” of the data.
In a network test and measurement situation, for a user of packet capture applications for network testing, creating an encoded packet filter or trigger specification, to look for data or activity on the network as a part of the testing/measuring, can be difficult and error-prone, as the different protocols and encodings that may be in use result in data on the network that is complex to decode manually. Translating values that a user is interested in to the specifications required by the string match algorithm can be difficult, because a given encoding may involve complex rules. But such translation is heretofore been required, so that the user can specify to the string match algorithm what it is that is to be matched.
Without the ability to filter data packets, high speed, high utilization interfaces common in computer networks can quickly fill the packet capture capability of software and hardware-based packet analysis applications and devices.
Accordingly, some manner of filtering and easily specifying the filter values becomes desirable.